A body covers the given distance first half of the time with a speed 58 kmph and second half of the time with a speed 75 kmph. Then the average speed of the body is.

$\begin{array}{l}\text{ Average Speed }=\frac{\text{ Total dis tan ce }}{\text{ Total time }}\\ =\frac{S_1+S_2}{t_1+t_2}\\ \text{ Where }{S}_1=V_1{t}_1=\frac{V_{1}t}{2}\\ S_2=V_2{t}_2=\frac{V_{2}t}{2}\\ \therefore \text{ Average speed }=\frac{\frac{V_{1}t}{2}+\frac{V_{2}t}{2}}{\frac{t}{2}+\frac{t}{2}}\end{array}$

                             $\begin{array}{l}=\frac{V_1+V_2}{2}=\frac{58+75}{2}\\ =\frac{133}{2}\\ =66.50\mathrm{kmph}\end{array}$